Stuttering playback & rendering

When I import a 4K video via media tab it plays fine. Smooth and easy to skip through with no issues. Add the same video to the timeline and the video stutters. Same stuttering observed in final rendered video

Videos are mov files from a DJI drone but have seen similar on a MOV from a D500.

Tried creating optimised media and ensuring the option to use it is ticked - same result.
Smart render cache used - same result.
Rebuilt all cache files - same result.

Can play the video smoothly ,full screen @ 4K, on the machine and it's as smooth as it gets. The fact it's smooth when imported or viewed via the media tab makes me suspect it's not the machine.

Suggestions?

[Peter Chamberlain]

Sounds like your clip and timeline frame rate is different so the are speeds changes applied.
viewtopic.php?f=21&t=69837

Yes, the frame rates vary, so that could be the issue but I'm still unclear why this should cause stuttering? Other video editors appear to cope and as the frame rates of the original clips are higher I wouldn't have expected an issue. Resolve 14.3 didn't display this issue...

I'll have a read about speed changes...

Resolve is trying to adapt different frame rates to the current timeline, which needs extra processing power. You need really beefy hardware to do that transparently for higher resolutions. Check what is set in your project for this function, optical flow is the slowest.

You can always avoid the problem by conforming the frame rate for those clips if their speed is not too far off, like 25 vs 24 or such.